Shredding equipment has been known for a number of years and the sizes and applications of such devices vary widely. In the yard and garden equipment industry, chipper shredders are becoming more commonplace as states and municipalities mandate the composting of yard and garden waste, or as operators of composting sites find that their operations can be run more efficiently if waste such as branches, fallen trees, and the like are comminuted before the material is put into windrows or piles. The smaller pieces resulting from such operations biodegrade more quickly under suitable moisture and oxygen conditions and the volume required for the ultimate disposal of the material is also reduced. In recent years, mobile shredding machines designed for large scale operations have been known, including those sold under the Jenz trademark by the assignee of the present invention. A brochure illustrating such machines is included with this specification.
Such machines have included a generally rectangular collection hopper which can be loaded by front end loaders and the like with debris to be comminuted. The floor of the bin is a first endless conveyor adapted to move the debris from a rear portion to the opposite end of the machine. Prior machines have also included an upper conveyor, inclined at an acute angle with respect to the floor conveyor, and adapted to assist in moving material toward the nip formed between the two conveyors. A rotating hammer mill has been located at the outlet of the nip to receive material being moved by the conveyors. The hammer mill includes a plurality of hammer knife elements and a stationary cutting surface, all as is well known in the comminuting art for dividing the material into fine pieces which are discharged at the rear of the machine. Various modifications which are not relevant to the present invention include providing screens on the rear of the hammer mill to cause particles to stay in the shredding section for a longer period of time so that the average particle size can be reduced, and various devices for directing the discharge to a desired outlet location, which could be a windrow, a pile or the like.
In such prior equipment, one frequently encountered problem has been the clogging of machines when large bunches of the debris are being forced by the two conveyors toward the nip. Such clogs, in prior machines, have been removed by stopping the equipment and manually releasing a clog by spreading the material out to avoid the bunching which caused the problem in the first place. Such operations result in reduced efficiency for the equipment, and a system which would overcome this problem would represent a substantial advance in this technology.